Method and system for image sensor and lens on a silicon back plane wafer

ABSTRACT

A method for forming image sensors includes providing a substrate and forming a plurality of photo diode regions, each of the photo diode regions being spatially disposed on the substrate. The method also includes forming an interlayer dielectric layer overlying the plurality of photo diode regions, forming a shielding layer formed overlying the interlayer dielectric layer, and applying a silicon dioxide bearing material overlying the shielding layer. The method further includes etching portions of the silicon dioxide bearing material to form a plurality of first lens structures, and continuing to form each of the plurality of first lens structures to provide a plurality of finished lens structures.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 11/952,901, filed on Dec. 7, 2007, which claims priority toChinese Application No. 200610119388.2, filed on Dec. 8, 2006; commonlyassigned, both of which are hereby incorporated by reference for allpurposes.

BACKGROUND OF THE INVENTION

The present invention is directed to integrated circuits and theirprocessing for the manufacture of electronic devices. More particularly,the invention provides a method for manufacturing an integrated lensstructure for an image sensing device. But it would be recognized thatthe invention has a much broader range of applicability.

Integrated circuits have evolved from a handful of interconnecteddevices fabricated on a single chip of silicon to millions of devices.Conventional integrated circuits provide performance and complexity farbeyond what was originally imagined. In order to achieve improvements incomplexity and circuit density (i.e., the number of devices capable ofbeing packed onto a given chip area), the size of the smallest devicefeature, also known as the device “geometry”, has become smaller witheach generation of integrated circuits.

Increasing circuit density has not only improved the complexity andperformance of integrated circuits but has also provided lower costparts to the consumer. An integrated circuit or chip fabricationfacility can cost hundreds of millions, or even billions, of U.S.dollars. Each fabrication facility will have a certain throughput ofwafers, and each wafer will have a certain number of integrated circuitson it. Therefore, by making the individual devices of an integratedcircuit smaller, more devices may be fabricated on each wafer, thusincreasing the output of the fabrication facility. Making devicessmaller is very challenging, as each process used in integratedfabrication has a limit. That is to say, a given process typically onlyworks down to a certain feature size, and then either the process or thedevice layout needs to be changed. Additionally, as devices requirefaster and faster designs, process limitations exist with certainconventional processes and materials.

An example of such a process is formation of device structures forimaging sensors such as charged coupled device (CCD), charge injecteddevices (CID), and others. Such imaging sensors (e.g., CCD, CID) includeadaptive arrays of stacked color filters provided on micro lenses, whichare incorporated into a silicon backplane. The silicon backplaneincludes MOS transistors and photo diode devices on the silicon wafersusing different materials and processes due to process incompatibility.Such processes rely upon different tools and materials. Micro lenses areoften stacked onto color filters, which are assembled using complex andcumbersome techniques. Accordingly, these sensors are often complex anddifficult to manufacture. These and other limitations have beendescribed in the present specification and more particularly below.

From the above, it is seen that an improved technique for processingdevices is desired.

BRIEF SUMMARY OF THE INVENTION

According to the present invention, techniques directed to integratedcircuits and their processing for the manufacture of electronic devicesare provided. More particularly, the invention provides a method formanufacturing an integrated lens structure for an image sensing device.But it would be recognized that the invention has a much broader rangeof applicability.

In a specific embodiment, the present invention provides an improvedimage sensor, e.g., CCD, CID, CMOS. The image sensor includes asubstrate, e.g., silicon wafer. The sensor also includes a plurality ofphoto diode regions, where each of the photo diode regions is spatiallydisposed on the substrate. The sensor has an interlayer dielectric layeroverlying the plurality of photo diode regions and a shielding layerformed overlying the interlayer dielectric layer. A silicon dioxidebearing material is overlying the shielding layer. A plurality of lensstructures are formed on the silicon dioxide bearing material. Thesensor also has a color filter layer overlying the lens structures and aplurality of second lens structures overlying the color filter layeraccording to a preferred embodiment.

In an alternative specific embodiment, the present invention provides amethod for forming image sensors, e.g., CCD, CID, CMOS. The methodincludes providing a substrate, e.g., silicon wafer. The method includesforming a plurality of photo diode regions, where each of the photodiode regions is spatially disposed on the substrate. The methodincludes forming an interlayer dielectric layer (e.g.,borophosphosilicate glass (BPSG), doped oxide, phosphosilicate glass(PSG), fluorinated silicate glass (FSG)) overlying the plurality ofphoto diode regions. The method includes forming a shielding layer(e.g., metal) formed overlying the interlayer dielectric layer andapplying a silicon dioxide bearing material overlying the shieldinglayer. The method includes etching portions of the silicon dioxidebearing material to form a plurality of first lens structures andcontinuing to form each of the plurality of first lens structures toprovide a plurality of finished lens structures.

Many benefits are achieved by way of the present invention overconventional techniques. For example, the present technique provides aneasy to use process that relies upon conventional technology. In someembodiments, the method provides higher device yields in dies per wafer.Additionally, the method provides a process that is compatible withconventional process technology without substantial modifications toconventional equipment and processes. Preferably, the invention providesfor an improved mirror and lens structure, which are integrated witheach other, for LCOS devices used for displays. Such integratedstructure can provide improved yields and process capabilities accordingto a specific embodiment. Depending upon the embodiment, one or more ofthese benefits may be achieved. These and other benefits will bedescribed in more throughout the present specification and moreparticularly below.

Various additional objects, features and advantages of the presentinvention can be more fully appreciated with reference to the detaileddescription and accompanying drawings that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified cross-sectional view diagram illustrating asensing device according to an embodiment of the present invention.

FIG. 2 is a simplified cross-sectional view diagram illustrating analternative sensing device according to an embodiment of the presentinvention.

FIG. 3 illustrates a method of fabricating a sensing device according toan embodiment of the present invention.

FIG. 4 illustrates an alternative method of fabricating a sensing deviceaccording to an embodiment of the present invention.

FIG. 5 is a simplified cross-sectional view diagram illustrating yet analternative sensing device according to an embodiment of the presentinvention.

FIG. 6 is a simplified cross-sectional view diagram illustrating stillan alternative sensing device according to an embodiment of the presentinvention.

FIG. 7 is a simplified cross-sectional view diagram illustrating stillan alternative sensing device according to an embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

According to the present invention, techniques directed to integratedcircuits and their processing for the manufacture of electronic devicesare provided. More particularly, the invention provides a method formanufacturing an integrated lens structure for an image sensing device.But it would be recognized that the invention has a much broader rangeof applicability.

FIG. 1 is a simplified cross-sectional view diagram illustrating asensing device 100 according to an embodiment of the present invention.This diagram is merely an example, which should not unduly limit thescope of the claims herein. One of ordinary skill in the art wouldrecognize many variations, modifications, and alternatives. As shown,the present invention provides an improved image sensor 100, e.g., CCD,CID, CMOS. The image sensor includes a substrate 101, e.g., siliconwafer. The sensor also includes a plurality of photo diode regions 103,where each of the photo diode regions is spatially disposed on thesubstrate. Each of the photo diode regions is also separated by aninsulating layer or isolation region, as shown. A plurality of MOSand/or CMOS devices 105 are also included. Such devices can be madeusing standard foundry compatible processes, and the like.

The sensor has an interlayer dielectric layer 107 overlying theplurality of photo diode regions. The interlayer dielectric can be asingle layer or multiple layers depending upon the specific embodiment.The layer can be made of a borophososilicate glass, phosophosilicateglass, fluorinated silicate glass, doped glass, or the like. Preferably,the interlayer dielectric layer has been planarized using chemicalmechanical planarization and/or resist etch back techniques, amongothers. Of course, one of ordinary skill in the art would recognize manyvariations, modifications, and alternatives.

Referring to FIG. 1, the sensor also has a shielding layer 113 formedoverlying the interlayer dielectric layer. The shielding layer can be ametal layer and/or other material that can block a selected portion ofelectromagnetic radiation, e.g., light. The shielding layer includes aplurality of openings, which allow light to traverse therethrough.Preferably, the shielding layer is made of a metal material, but can bemade of any other single or combination of materials.

A silicon dioxide bearing material 117 is overlying the shielding layeras shown. A plurality of lens structures 119 are formed on the silicondioxide bearing material. Other types of suitable materials can also beused for the lens structures. That is, any combination of layers ormaterials can be used with suitable lens characteristics. Each of thelens structures is annular and/or spherical in shape, depending upon theembodiment. Specific details on ways of fabricating the plurality oflens structures can be found throughout the present specification andmore particularly below.

A planarizing layer 121 or glue layer is formed overlying the pluralityof lens structures. The planarizing layer is preferably made of anorganic type material such as polyimide and the like. The planarizinglayer serves as a “glue” layer between the silicon lens structures andoverlying color filter layer 123. The color filter layer has beenpatterned into an array structure depending upon the embodiment.Preferably, the color filter array includes colors such as red (R),green (G), and blue (B), depending upon the embodiment. As shown, thesensor also has the color filter layer overlying the lens structures.Overlying the color filter array is a passivation coating. Thepassivation coating can include any suitable materials such as apolymeric material. Other materials may also be used depending upon theapplication. Of course, one of ordinary skill in the art would recognizemany variations, modifications, and alternatives.

In operation, light 127 falls onto the surfaces of a passivation layer125. The light traverses through color filter array 123, where selectedcolors pass through selected spatial regions to illuminate a color fromthe RGB (red, green, and blue) pixel arrays. The light traverses 129through the glue layer and through 131 each of the lens structures. Eachof the lens structures focuses the light 135, which falls 137 onto photodiode 139, to cause a change in electrical characteristic of the photodiode. The change can be sensed using sensing circuitry, which iscoupled to logic circuitry. As also shown, the shielding layer blocks133 certain portions of light that are not focused onto the photo diodeaccording to a preferred embodiment. Of course, there can be othervariations, modifications, and alternatives.

It is also understood that the examples and embodiments described hereinare for illustrative purposes only and that various modifications orchanges in light thereof will be suggested to persons skilled in the artand are to be included within the spirit and purview of this applicationand scope of the appended claims.

FIG. 2 is a simplified cross-sectional view diagram illustrating analternative sensing device 200 according to an embodiment of the presentinvention. This diagram is merely an example, which should not undulylimit the scope of the claims herein. One of ordinary skill in the artwould recognize many variations, modifications, and alternatives. Asshown, the present invention provides an improved image sensor, e.g.,CCD, CID, CMOS. The image sensor includes a substrate, e.g., siliconwafer. The sensor also includes a plurality of photo diode regions,where each of the photo diode regions is spatially disposed on thesubstrate. Each of the photo diode regions is also separated by aninsulating layer or isolation region, as shown. A plurality of MOSand/or CMOS devices are also included. Such devices can be made usingstandard foundry compatible processes, and the like.

The sensor has an interlayer dielectric layer overlying the plurality ofphoto diode regions. The interlayer dielectric can be a single layer ormultiple layers depending upon the specific embodiment. The layer can bemade of a borophososilicate glass, phosophosilicate glass, fluorinatedsilicate glass, doped glass, or the like. Preferably, the interlayerdielectric layer has been planarized using chemical mechanicalplanarization and/or resist etch back techniques, among others. Ofcourse, one of ordinary skill in the art would recognize manyvariations, modifications, and alternatives.

Referring again to FIG. 2, the sensor also has a shielding layer formedoverlying the interlayer dielectric layer. The shielding layer can be ametal layer and/or other material that can block a selected portion ofelectromagnetic radiation, e.g., light. The shielding layer includes aplurality of openings, which allow light to traverse therethrough.Preferably, the shielding layer is made of aluminum material, but can bemade of any other single or combination of materials.

A silicon dioxide bearing material is overlying the shielding layer asshown. A plurality of lens structures 215 are formed on the silicondioxide bearing material. Other types of suitable materials can also beused for the lens structures. That is, any combination of layers ormaterials can be used with suitable lens characteristics. Each of thelens structures is annular and/or spherical in shape, depending upon theembodiment. Specific details on ways of fabricating the plurality oflens structures can be found throughout the present specification andmore particularly below.

A planarizing layer or glue layer is formed overlying the plurality oflens structures. The planarizing layer is preferably made of an organictype material such as polyimide, and the like. The planarizing layerserves as a “glue” layer between the silicon lens structures andoverlying color filter layer. The color filter layer has been patternedinto an array structure depending upon the embodiment. Preferably, thecolor filter array includes colors such as red (R), green (G), and blue(B), depending upon the embodiment. As shown, the sensor also has thecolor filter layer overlying the lens structures.

Overlying the color filter layer is a clear coating layer 210. The clearcoating layer can be a polyimide layer or other type of material ormaterials. A plurality of lens structures 207 are formed in the clearcoating layer. Overlying the lens structures is a passivation coating209. The passivation coating can include any suitable materials such asa clear polymer material and the like. Of course, one of ordinary skillin the art would recognize many variations, modifications, andalternatives.

In operation, light 211 falls onto the surfaces of the passivationlayer. The light traverses through 213 lens structure 207 and through215 color filter array 205, where selected colors pass through selectedspatial regions to illuminate a color from the RGB pixel arrays. Asshown, the light traverses 217 through the glue layer and through eachof the lens structures. Each of the lens structures focuses the light219, which falls onto photo diode 221, to cause a change in electricalcharacteristic of the photo diode. The change can be sensed usingsensing circuitry, which is coupled to logic circuitry. The shieldinglayer blocks certain portions of light that are not focused onto thephoto diode according to a preferred embodiment. Of course, there can beother variations, modifications, and alternatives.

It is also understood that the examples and embodiments described hereinare for illustrative purposes only and that various modifications orchanges in light thereof will be suggested to persons skilled in the artand are to be included within the spirit and purview of this applicationand scope of the appended claims.

A method for fabricating a sensing device having an integrated lensstructure according to an embodiment of the present invention may beoutlined as follows:

1. Provide a substrate, e.g., silicon wafer.

2. Form a plurality of photo diode regions, where each of the photodiode regions is spatially disposed on the substrate, and form aplurality of MOS/CMOS transistors on the substrate;

3. Form an interlayer dielectric layer (e.g., borophosphosilicate glass(BPSG), doped oxide, phosphosilicate glass (PSG), fluorinated silicateglass (FSG)) overlying the plurality of photo diode regions and MOS/CMOStransistors;

4. Form a shielding layer (e.g., metal)formed overlying the interlayerdielectric layer;

5. Pattern the shielding layer;

6. Apply a silicon dioxide bearing material overlying the shieldinglayer;

7. Planarize the silicon dioxide layer;

8. Etch portions of the silicon dioxide bearing material to form aplurality of first lens structures; and

9. Continue to form each of the plurality of first lens structures toprovide a plurality of finished lens structures; and

10. Perform other steps, as desired.

The above sequence of steps provides a method according to an embodimentof the present invention. As shown, the method uses a combination ofsteps including a way of forming an integrated lens structure for asensing device according to an embodiment of the present invention.Other alternatives can also be provided where steps are added, one ormore steps are removed, or one or more steps are provided in a differentsequence without departing from the scope of the claims herein. Furtherdetails of the present method can be found throughout the presentspecification and more particularly below.

FIG. 3 illustrates a method of fabricating sensing device 200 accordingto an embodiment of the present invention. This diagram is merely anexample, which should not unduly limit the scope of the claims herein.One of ordinary skill in the art would recognize many variations,modifications, and alternatives. As shown, the method focuses on a wayof fabricating the lens structure on a silicon backplane according to aspecific embodiment. The method includes providing a silicon dioxidelayer 301, which has been deposited. The layer also has suitablecharacteristics for the present lens structures. The method forms aplurality of photoresist 307 regions overlying selected portions of thesilicon dioxide layer. The photoresist regions may be characterized byan annular shape, which can be formed using different exposures,provided on the photoresist regions. The photoresist regions exposeregion 309, which will be etched. The photoresist region is formedoverlying region 305, which will serve as a lens structure, according toa specific embodiment of the present invention.

Using the photoresist as a blocking layer, the method etches the exposedregions 311, as shown. As the method etches the exposed region, portionsof the photoresist 313 remain as other portions are removed, to form anannular shaped lens structure 315 having a suitable focal length. Ofcourse, one of ordinary skill in the art would recognize manyvariations, modifications, and alternatives. The completed structure isillustrated by way of reference numeral 300 in FIG. 3, as shown. Thecompleted structure includes various elements such as substrate,devices, interlayer dielectric layer, metal layers, shielding layer, andlens array. Other elements would also be included to form the finisheddevice according to a specific embodiment. Alternative methods forfabricating the present device can be found throughout the presentspecification and more particularly below.

FIG. 4 illustrates an alternative method of fabricating a sensing device400 according to an embodiment of the present invention. This diagram ismerely an example, which should not unduly limit the scope of the claimsherein. One of ordinary skill in the art would recognize manyvariations, modifications, and alternatives. As shown, the sensingdevice includes silicon dioxide layer formed on a silicon backplane. Thedevice also includes other elements such as substrate, photodiodes andMOS/CMOS devices, metal interconnects, interlayer dielectric material,shielding layer, among others. The silicon dioxide layer would be usedto form a plurality of lens structures 405, as also shown. Preferably,the method includes forming a photo masking layer 401 overlying thesilicon dioxide layer. The masking layer is developed 403 and patternedto form a plurality of photo patterns 407. Each of the photo patternswould be used to form lens structure 405 in the silicon dioxide layer.The photo pattern has sharp edges, which are made using the developmentand patterning process. A thermal treatment is performed on the photopattern to round the edges of each of the photo patterns. The roundededges for a plurality of annular photo pattern regions 409 overlyingeach of the lens structures to be formed. Each of the annular photopattern regions includes sloped edges that form a resulting thickness ofmaterial that is thinner around a periphery of the region and thickernear a center of the region, as shown. Each of the regions exhibit ashape of a fluid material, which is thicker in the center and thinneralong the peripheral edges. Of course, one of ordinary skill in the artwould recognize many variations, modifications, and alternatives.

FIG. 5 is a simplified cross-sectional view diagram illustrating yet analternative sensing device 500 according to an embodiment of the presentinvention. This diagram is merely an example, which should not undulylimit the scope of the claims herein. One of ordinary skill in the artwould recognize many variations, modifications, and alternatives. Asshown, the device includes common elements as the prior embodiments.Such elements include substrate, photo diodes and CMOS/MOS devices,metal interconnects, interlayer dielectric material, and shielding layer503.

The device also includes a plurality of lens structures 501, which areformed in a plane within a vicinity of a surface of a shielding layer503, as shown. Each of the lens structures is made of a suitablematerial such as silicon dioxide or the like. The device also has anoverlying planarization layer, a color filter array, and passivationcoating, among other elements. Of course, one of ordinary skill in theart would recognize many variations, modifications, and alternatives.

FIG. 6 is a simplified cross-sectional view diagram illustrating stillan alternative sensing device 600 according to an embodiment of thepresent invention. This diagram is merely an example, which should notunduly limit the scope of the claims herein. One of ordinary skill inthe art would recognize many variations, modifications, andalternatives. The sensing device is preferably for a “black and white”integrated circuit sensing chip. As such, the device is free from acolor filter assembly or array provided on the device. As shown, thedevice includes common elements as the prior embodiments. Such elementsinclude substrate, photo diodes and CMOS/MOS devices, metalinterconnects, interlayer dielectric material, shielding layer, andsilicon dioxide layer.

The device also includes a plurality of lens structures 601, which areformed in the silicon dioxide layer, as shown. Each of the lensstructures is made of a suitable material such as silicon dioxide or thelike. The device does not have an overlying planarization layer, a colorfilter array, and passivation coating, among other elements. Of course,one of ordinary skill in the art would recognize many variations,modifications, and alternatives.

A method for fabricating a sensing device having an integrated lensstructure according to an embodiment of the present invention may beoutlined as follows:

1. Provide a substrate, e.g., silicon wafer.

2. Form a plurality of photo diode regions, where each of the photodiode regions is spatially disposed on the substrate, and form aplurality of MOS/CMOS transistors on the substrate;

3. Form an interlayer dielectric layer (e.g., borophosphosilicate glass(BPSG), doped oxide, phosphosilicate glass (PSG), fluorinated silicateglass (FSG)) overlying the plurality of photo diode regions and MOS/CMOStransistors;

4. Form a shielding layer (e.g., metal) formed overlying the interlayerdielectric layer;

5. Pattern the shielding layer;

6. Apply a silicon dioxide bearing material overlying the shieldinglayer;

7. Planarize the silicon dioxide layer;

8. Form a patterned mask on the silicon dioxide layer;

9. Etch portions of the silicon dioxide bearing material to form aplurality of first lens structures, each of which is characterized as anisland of silicon dioxide bearing material having edges; and

10. Strip patterned mask;

11. Deposit a conformal layer over lens material overlying each of theislands to provide a plurality of finished lens structures; and

12. Perform other steps, as desired.

The above sequence of steps provides a method according to an embodimentof the present invention. As shown, the method uses a combination ofsteps including a way of forming an integrated lens structure for asensing device according to an embodiment of the present invention. Theintegrated lens structures include etching and deposition of materialsto form the lens structures according to a preferred embodiment. Otheralternatives can also be provided where steps are added, one or moresteps are removed, or one or more steps are provided in a differentsequence without departing from the scope of the claims herein. Furtherdetails of the present method can be found throughout the presentspecification and more particularly below.

FIG. 7 is a simplified cross-sectional view diagram illustrating stillan alternative sensing device 700 according to an embodiment of thepresent invention. This diagram is merely an example, which should notunduly limit the scope of the claims herein. One of ordinary skill inthe art would recognize many variations, modifications, andalternatives. As shown, the device includes common elements as the priorembodiments. Such elements include substrate, photo diodes and CMOS/MOSdevices, metal interconnects, interlayer dielectric material, andshielding layer.

The device also includes a plurality of lens structures 711, which areformed using a combination of etching and deposition, as shown. Each ofthe lens structures is made of a suitable material such as silicondioxide or the like. The device may also have an overlying planarizationlayer, a color filter array, and passivation coating, among otherelements. Of course, one of ordinary skill in the art would recognizemany variations, modifications, and alternatives.

To manufacture the lens structures, the method includes providing thesilicon dioxide or lens material layer 703, which will include the lensstructures 705 (see doted line). A patterned masking layer 709 is formedon the surface of the silicon dioxide layer. The silicon dioxide layeris then etched to form islands 707 of lens regions. As shown, themasking layer has vertical edges and is common to conventionalphotolithography techniques. Depending upon the specific embodiment,plasma etching and/or other etching techniques known in the art can beused. Next, the method deposits 711 a thickness of lens materialoverlying the islands of silicon dioxide regions. The thickness of lensmaterial is conformal and forms an annular lens structure, as shown. Thethickness of material is deposited in a blanket fashion overlying theexposed surfaces, including island structures, to form the annularand/or spherical lens structures. Of course, one of ordinary skill inthe art would recognize many other variations, modifications, andalternatives.

It is also understood that the examples and embodiments described hereinare for illustrative purposes only and that various modifications orchanges in light thereof will be suggested to persons skilled in the artand are to be included within the spirit and purview of this applicationand scope of the appended claims.

What is claimed is:
 1. A method for forming image sensors, the methodcomprising: providing a substrate; forming a plurality of photo dioderegions, each of the photo diode regions being spatially disposed on thesubstrate; forming one or more interconnect layers overlying theplurality of photo diode regions; forming an interlayer dielectric layeroverlying all the interconnect layers; forming a shielding layeroverlying the interlayer dielectric layer, the shielding layer havingopenings only above the plurality of photo diode regions to allow lightto reach the photo diode regions; and forming a plurality of lensstructures comprising a silicon dioxide bearing material overlying theshielding layer, wherein the shielding layer comprises openings onlyunderneath the plurality of lens structures and is configured to shieldregions not underneath the lens structures.
 2. The method of claim 1further comprising forming a color filter layer overlying the lensstructures and forming a plurality of second lens structures overlyingthe color filter layer.
 3. The method of claim 1 further comprisingforming a planarizing layer overlying the plurality of lens structuresformed on the silicon dioxide material.
 4. The method of claim 1 whereinthe shielding layer comprises a metal bearing material.
 5. The method ofclaim 1 wherein the plurality of lens structures are formed in thesilicon dioxide bearing material using an etching process.
 6. The methodof claim 1 further comprising forming an organic planarized layeroverlying the plurality of lens structures, forming a color filter arrayoverlying the planarized layer, and forming a plurality of second lensstructures overlying the color filter array.
 7. The method of claim 6further comprising forming a planarized overcoat layer overlying theplurality of second lens structures.
 8. The method of claim 1 whereinthe substrate is a silicon wafer.
 9. The method of claim 1 furthercomprising forming a plurality of MOS transistor regions formed on thesubstrate.
 10. The method of claim 1 the etching and continuing compriseforming a patterned mask layer overlying the silicon dioxide bearingmaterial and etching exposed portions of the patterned mask layer. 11.The method of claim 1 wherein each of the plurality of first lensstructures provides for focusing onto respective photodiode deviceregion.
 12. The method of claim 1 wherein each of the plurality of firstlens structures has a refractive index ranging from about 1.44 to about1.46.
 13. The method of claim 1 wherein each of the plurality of firstlens structures is characterized by an annular shape.
 14. The method ofclaim 13 wherein the annular shape is spherical.
 15. The method of claim1 wherein the continuing to form comprises depositing a lens materialoverlying each of the first lens structures to form each of theplurality of finished lens structures.
 16. The method of claim 15wherein each of the finished lens structures is partially finished. 17.A method for forming an image sensor, comprising: forming a substrate;forming a plurality of photo diode regions, each of the photo dioderegions being spatially disposed on the substrate; forming one or moreinterconnect layers overlying the plurality of photo diode regions;forming an interlayer dielectric layer overlying the one or moreinterconnect layers; forming a shielding layer overlying the interlayerdielectric layer and the interconnect layers, the shielding layer havingopenings only above the plurality of photo diode regions to allow lightto reach the photo diode regions; and forming a plurality of lensstructures comprising a silicon dioxide bearing material overlying theshielding layer.
 18. A method for forming an image sensor, comprising:forming a substrate; forming a plurality of photo diode regions, each ofthe photo diode regions being spatially disposed on the substrate;forming one or more interconnect layers overlying the plurality of photodiode regions; an interlayer dielectric layer overlying the one or moreinterconnect layers and the plurality of photo diode regions; forming ashielding layer formed overlying the interlayer dielectric layer andsubstantially covers the interlayer dielectric layer with openings onlyoverlying the plurality of photo diode regions; and forming a pluralityof lens structures directly above the shielding layer with nointervening layers.
 19. The method of claim 11, further comprisingforming at least one of the plurality of lens structures is in directcontact with the shielding layer.